An evaluation of patents in this field (status indicators for circuit breakers, switches, or fuses) reveals that existing technology is significantly different from, and inferior to, that claimed by the applicant.
Relevant U.S. patents examined were: U.S. Pat. No. 4,056,816 (Guim), U.S. Pat. No. 4,652,867 (Masot), U.S. Pat. No. 4,672,351 (Cheng), U.S. Pat. No. 5,233,330 (Hase), U.S. Pat. No. 5,343,192 (Yenisey), U.S. Pat. No. 5,353,014 (Carroll et al.), U.S. Pat. No. 5,812,352 (Rokita et al.), and U.S. Pat. No. 5,920,451 (Fasano et al.)
Evaluation of relevant patents in this field has revealed that:                All previously issued patents describe a circuit that uses a single indicator to indicate either the “OPEN/TRIPPED” or the “CLOSED” position, or uses multiple indicators (usually separate LEDs) to display multiple possible conditions. Existing technology does not allow a single lighted display element to indicate status for all possible breaker, switch, or fuse conditions.        Some of the issued patents require that a parallel circuit or set of contacts be implemented together with the circuit breaker, switch, or fuse in order to activate the indicator light.        Some patents in this area require active elements to monitor the status of the circuit breaker or switch. Such circuits are less reliable and more expensive than circuits that use only passive elements.        Some of the previously issued patents apply only to AC or DC powered systems. Those used in DC systems may or may not function with both polarities.        None of the technologies in existing patents incorporates a momentary test switch circuit that allows all circuit breaker, switch, or fuse status indicators to be simultaneously tested, using a single bi-color lighted status indicator per breaker/switch.        Finally, all circuits described in related patents are designed to be used with specific supply voltages and will not function correctly outside that supply range.        
The invention claimed by the applicants addresses all these problems. It describes a circuit breaker, switch, or fuse status indicator that incorporates a lighted visual display with a multi-color light source, eliminating the need for multiple light sources (such as LEDs or back-lit LCDs) to display the various possible positions of a breaker.
A circuit that uses a single multi-color light source for status display is superior to existing circuits with multiple light sources. Using of multiple light sources introduces extra expense and complexity to status indicator circuitry and can unnecessarily consume scarce room on the front of circuit breaker (or a panel adjacent to the circuit breaker).
The circuit breaker status indicator uses an inexpensive, passive electronic circuit that takes advantage of the status contact switch of the circuit breaker to change the color of that light source, depending upon the status (or position) of the circuit breaker. This circuit can also easily be configured to support a wide range of AC and DC (both positive and negative) voltages, and to include a momentary test switch circuit.